Tower for a wind turbine

ABSTRACT

The invention relates to a tower for a wind turbine and to a cable guide therefor, wherein a nacelle is arranged on the tower such that it can rotate by means of the azimuth bearing about a vertical axis which runs in the longitudinal direction of the tower. A guide device is arranged between a cable bundle and the tower, wherein the guiding device has means for supporting the lower area of the cable bundle in a radial direction, and for supporting with respect to the tower in a circumferential direction.

This application is a 371 application of PCT/EP2011/059231 filed Jun. 3,2011, which claims foreign priority benefit under 35 U.S.C. §119 ofGerman application 10 2010 022 581.2 filed Jun. 3, 2010.

The invention relates to a tower for a wind turbine and to a cable guidefor a tower of a wind turbine, wherein a nacelle for the wind turbine isarranged on the tower such that it can rotate about an axis which runsvertically in the longitudinal direction of the tower by means of theazimuth bearing. A generator for generating electrical energy isprovided which can be driven by a rotor of the wind turbine, is providedin the nacelle. The azimuth bearing allows a horizontal orientation ofthe nacelle according to the wind direction which is called ‘windtracking’ of the wind turbine. For automatic alignment of the nacelle onthe azimuth bearing one or more azimuth drives are provided which arenon-rotatably connected to the machine carrier of the nacelle. In thiscase, the azimuth bearings must transmit the appearing bearing forcessuch as thrust, centrifugal and yaw forces, from the machine carrier ofthe nacelle into the tower.

During wind tracking—also described as ‘yawing’—the nacelle is rotatedaround a vertical axis of rotation in the horizontal plane in orderrotate the rotor perpendicularly in the wind and consequently tomaximize the energy output. Since the wind direction varies or evenrotates it may be possible that the nacelle is rotated around its ownaxis several times.

In the tower of the wind turbine current conducting cables, such aspower cables, are routed from electrical components out of the nacelleto the ground. These are a plurality of cables, for example a pluralityof cables for electrical conduction of individual phases of alternatingcurrent, in particular three-phase alternating current, cables forearthing conductor and/or signal and control cables. The exact number ofthe cables—in particular the power cables—is dependent on the crosssection of the individual electrical conductors and the nominal currentto be transmitted. Usually the current conducting capacity of a singleconductor of the power cable is too small to transmit the nominalcurrent, and therefore the nominal current is divided to a plurality ofpower cables.

The statements of axial direction, radial direction, circumferentialdirection used below and statements about the top and bottom are validwith respect to the tower axis of the erected tower of the wind turbine.

The cables are fixedly arranged in a lower portion of the towerpreferably by means of cable terminals on the tower wall. In a middlepart of the tower the cables are guided through a cable support into aradially central portion of the tower interior. From there the cablesextend centrally and freely suspended to an upper end of the tower andinto the nacelle. To prevent the cables of excessive swinging it isknown that the cables are led through a tube, preferably a polyethylenetube, and through a circular opening in the topmost platform of thetower. By guiding the cable through the tube, the cable will becollected in a large bundle. The bundling and mutual induction ofclosely packed current-conducting cables may result into a reducedcurrent conducting capacity of the cables. Now if the nacelle rotatesaround its own axis several times because of wind tracking the cablesare twisted which results in a shortening of the cables. This can resultin damage or wear of the insulation due to friction between theindividual cables which creates a major safety hazard. Moreover, theindividual cables get closer to each other thus the current conductingcapacity of the cables is reduced. This has the result that the requirednumber of cables for transmitting the nominal current increases thereforthe associated cost increase.

It is an object of the invention to provide an improved guidance of thecables which i.e. avoids the disadvantages of the prior art. Inparticular it is to be achieved that the current conducting capacity ofthe cables is secured and/or the wear between the cables is reduced.

According to the invention the object is solved with the features of theclaim 1 wherein, while in the tower a guiding device for at leastpartially fixing the area of the cable bundle to the tower iseffectively arranged between the cable bundle and the tower, wherein theguiding device comprises means for supporting the lower region of thecable bundle in a radial direction and for supporting in acircumferential direction relative to the tower. The guiding device isconfigured in such a manner that the lower region of the cable bundle issupported to be movable in the axial direction relative to the tower butis substantially fixed in the circumferential and radial directionrelative to the tower. Thus the guiding device causes that an axialdisplacement of the cable bundle and in particular an axial displacementof the lower region of the cable bundle is achieved through the cableguide and at the same time always a defined position of the cable bundleand defined configuration of the cable of the cable bundle is ensured.

One embodiment cites that a cable loop is provided, wherein a first endof the conductor loop is directly connected to the lower region of thecable bundle approximately at the center of the tower interior and iselectrically connected thereto, and a second end of the conductor loopon the tower wall is fixedly connected to the tower and electricallyconnected to further leading cables which are fixed with the tower. Thetwisting of the cables causes the cable bundle to shortened in the axialdirection. The cables are guided in the cable loop so that a freerotation of the nacelle is not prevented by a clamping of the cable andthe cable would not be damaged. The shortening of the cable bundle iscompensated by the excess of cable in the cable loop. It is advantageousif the cables of the cable bundle, the cable loop and the cable fixedwith the tower are formed continuously and in one piece and withoutinterruption. In other words, each cable is continuously guided from thenacelle to the foot of the tower or from the upper end of the cablebundle through the lower region of the cable bundle, passing through thecable loop over to the cable guide fixed with the tower and down toelectrical terminals in the base of the tower.

By fixing the cable bundle through the guiding device in thecircumferential direction for the first time it is possible toeffectively prevent an uncontrolled rotation of the cable of the cableloop and thus to ensure the minimum distance of the cable with respectto each other.

According to another embodiment the guiding device comprises a bundlingdevice for bundling and fixing the cables of the cable loop. Thebundling device is arranged at the lower portion of the cable bundle orat the first end of the cable loop. Here it is ensured by geometricfeatures of the bundling devices that at least between three cables acertain minimum distance is available in each state to prevent areduction in the current conducting capacity of different cables bymutual induction in accordance with IEC 60364-5-52 and it does not fallbelow the certain minimum distance. By ‘each state’ it is meant that ineach operating condition of the wind turbine and in each intendedazimuth position of the nacelle the cables are spaced at a minimumdistance and a mutual induction is reduced and the current conductingcapacity is ensured.

According to a preferred embodiment the bundling device is configured insuch a manner that all the adjacent power cables are spaced at theminimum distance. In the case of a wind turbine with a doubly-fedasynchronous generator wherein the converter unit is arranged in thefoot of the tower the cables can be embodied as a plurality of powercables extending from the stator, preferably also be power cablesextending from the generator rotor and/or earthing cables.

In case that a multi-phase, in particular three-phase current is ledthrough the cable, in particular through the power cable, each powercable comprises three individual conductors. These conductors may becombined together since the magnetic fields of the respective phases ofthe current are canceled out against each other. Within the scope ofthis invention this multiphase cable with combined conductors isconsidered as a cable or as a current-conducting cable, especially powercable. The individual conductors not necessarily have to be surroundedby a common cover. This applies for example to combine the three phasesof a three-phase current in a cloverleaf structure.

According to a further embodiment the bundling device is designed insuch a manner that all the adjacent cables such as power cables,earthing cables and control and signal cables are spaced with theminimum distance.

In another embodiment the bundling device comprises fastening devicesfor arranging the cables. These can be arranged on the bundling devicein such way that the cables are arranged in a polygonal and equilateralstructure. The structure can be for example the shape of an equilateraltriangle, a square, a regular pentagon, or a polygonal and equilateralshape with a plurality of corners. However, the number of corners andsides must be at least the same as the number of the cables, the powercables, or the current-conducting cables to be separated by means of theminimum distance. The fastening devices are arranged in such a mannerthat the distance between the closest in the receptacles fastened cablesshows a minimum distance for preventing a reduction of the currentconducting capacity of different cables by mutual induction according toIEC 60364-5-52. By keeping the minimum distance of the cables withrespect to each other the current conducting capacity of the cable isoptimized so that the number of cables required for transferring thenominal current can be reduced. This is particularly important in thecable routing of wind turbines since very high power is passed throughthe tower.

The polygonal and equilateral feature of the bundling device has theadvantage that the distance of the individual cables with respect toeach other is maximal when the overall size of the bundling device isminimal and consequently the electromagnetic interference of the cablewith each other is minimized. The smallest possible diameter of thebundling device is most favorable with regard to the shortening of thecable bundle caused by twisting. The distance between the receptacles ofthe clamping clips therefore should be kept as short as possible so thatthe excess of cables for compensating the shortening of the bundle canbe kept as small as possible.

In a preferred embodiment, the fastening devices are arranged in such amanner that the structure of the receptacles has an additional cornerand side. The receptacle which is thereby available additionally, servesto accommodate the cable of the neutral conductor in such so that aminimum distance according to IEC 60364-5-52 is also available betweenthe cable of the neutral conductor and the nearest current-conductingcables.

In a particularly preferred embodiment, the fastening devices arearranged in such a manner that the structure of the receptacles hasexactly the same number of corners and sides as the number of theexisting cables. The receptacles which are thereby availableadditionally, serves to accommodate signal lines so that between signallines and the closest current-conducting cables or cables of the neutralconductor a minimum distance according to IEC 60364-5-52 is alsoavailable.

In one embodiment, the bundling device comprises a carrier on which thefastening devices are arranged to attach the cables to the bundlingdevice. In this case, the fastening device has a receptacle forreceiving the cables. The carrier may be formed in one piece ormulti-piece. It is also conceivable that the carrier is formed at leastpartially through the fastening devices or the fastening devices areformed at least partially through the carrier. Thereby for example,several fastening devices would be assembled together so that thiscombined structure takes over the function of the carrier. The bundlingdevice can be extended by attaching more clamping clips easily to theexisting number of cables which saves money on installation and storageof spare parts for the bundling device.

The fastening devices are preferably configured as clamping clips whichcan be attached to the carrier by means of fastening elements. Thefastening elements can e.g. be screws. In a first embodiment theclamping clips are non-rotatably connected to the carrier and formed inone piece so that the clamping clips together with the carrier form thefastening device. The clamping clips are advantageously formed in an arcshape so that a receptacle for a cable or for a cable with a pluralityof conductors is formed. The cable which is situated in the receptacle,is clamped between the clamping clip and the carrier when mounting theclamping clip onto the carrier so that the bundling device is firmlyconnected to the cable.

In a preferred embodiment the clamping clip is formed as a V-shaped arcso that the receptacle has a triangular cross-section. This has theadvantage that in a three-phase cable comprising three conductors thecurrent-conducting cable is fixed by the clamping clip in the cloverleafstructure. In the case that cables with smaller diameters, for examplesignal cables, are available the receptacles may comprise an insert thatreduces the size of the receptacle.

In one embodiment, the fastening devices are in each case arranged onthe carrier to be rotatable about an axis which substantially extends inradial direction. Through the rotatable arrangement of the fasteningdevices the fastening devices can rotate with the twisting of the cableso that a normal axis to the triangular cross section of the receptacleof the fastening devices extends always parallel to a longitudinal axisof the cables. Thus, both the load on the cable as well as the load onthe fastening devices and their connection elements can be reduced. Thefastening device in this embodiment is configured in several pieces.

The features of the bundling devices act not in a limiting way onto thefollowing embodiments.

A further aspect of the invention discloses that a cable support forarranging the individual cables of the cable loop is provided to beconnected to the tower. This cable support is configured in such amanner that the cable can be arranged thereon so that at least threecables in the cable loop have in each state a minimum distance forpreventing a reduction of the current conducting capacity of differentcables by mutual induction according to IEC 60364-5-52. Analogous to theabove-described, the cable support can also be configured in such amanner that all adjacent cables such as power cables, earthing cablesand control and signal cables are at least partially spaced at a minimumdistance.

In an advantageous manner the supporting means of the guiding device canbe configured as a pivot arm. This pivot arm is connected to the towerat a side facing a tower inner wall in a way of being rotatable about apivot axis and is connected to the cable bundle at a side facing thetower interior in a way of being rotatable about a rotation axis,particularly connected to the bundling device at the lower end of thecable bundle. The pivot axis and/or the rotation axis extendsubstantially horizontally and perpendicularly to the axial direction.In this way, the guiding device can be realized in a simple manner.

If the cable bundle is not rotated, the pivot arm is located in asubstantially horizontal position wherein the bundling device issubstantially coaxially aligned with the tower axis. If the cable bundleis shortened due to the rotation of the cable bundle, the pivot arm ispulled upwards with the lower region of the cable bundle. Thecompensation of axial shortening is achieved by the cable loop.

A further embodiment cites that the pivot arm in not rotated cablebundle is slightly inclined downwards. Thereby, the lower region of thecable bundle is arranged to be slightly radially offset to the toweraxis. This has the advantage that with increasing rotation the maximumradial displacement of the pivot arm is reduced in relation to thepreceding embodiment. This allows for an increased range of angles forthe wind tracking.

In an alternative manner, the said guide means may comprise means forsupporting which are formed as a rail arrangement. This rail arrangementcomprises a first rail element and a second rail element. Here a firstrail member is connected to the lower region of the cable bundle, and asecond rail element is connected to the tower. Both of the rail elementsengage in the radial direction and in the circumferential direction in aform-locking way so that a support of the lower region of the cablebundle in the radial direction and circumferential direction relative tothe tower is possible, and wherein the first rail element and the secondrail element are configured to be geometrically uncrossed in the axialdirection so that a axial displacement of the lower region of the cablebundle with respect to the tower is possible. In the case of theshortening of the cable bundle, the rail element connected to the cablebundle slides axially upwardly, wherein the compensation of the lengthis carried out by the cable loop. It is conceivable that a plurality ofrail assemblies is provided.

It is advantageous, but not acting in a limiting way on the followingand preceding embodiments if the tower has at least two bundling deviceswhich are suitable for combining the individual cables which extendslongitudinally in the tower to a mutually fixed cable bundle. Thebundling devices are mounted on the cables between the upper and thelower region of the cable bundle.

Advantageously, the tower comprises a plurality of bundling deviceswhich are fastened to the cables with regular distances between theupper and the lower region of the cable bundle. The distance between thebundling devices is selected in such a manner that a twisting of thecables is indeed allowed, but the cables still have the prescribedminimum distance with respect to each other even at a maximum rotationof the nacelle.

The cable bundles advantageously have an axial distance of 500 to 1000mm with respect to each other, particularly advantageous the distancesare between 500 and 600 mm. The cable bundle hangs for the most partfreely in the tower of the wind turbine, and is non-rotatably connectedto the nacelle only at the upper part and non-rotatably connected to aguiding device at the lower region. The cable bundle is self-supportingand is stabilized by the bundling devices.

Due to movement of the tower and due to resonance, it can result in aswinging of the cable bundle in the radial direction. In order to limitthe radial movement of cable bundle, in another embodiment, the towerincludes at least one axially effective ring guide which is fixedlyconnected to the tower. The cable bundle is guided through the ringguide and then hangs for the most part freely in the tower of the windturbine. Conveniently, several ring guides are used, preferably two,particularly preferably three, and most preferably four ring guides.This support also serves to preserve the cable distance from a possiblymetallic guide ring.

In a further embodiment, the radial support can connect at least twosuccessive bundling devices. In this embodiment, the axial length of theradial support must be greater than the axial shortening of the cablebundle which is generated in the actual section. Because only in thisway it can be ensured that the support may be in contact with the ringguide during the entire axial movement of the cable bundle.

In particular, the distances between the bundling devices connected bythe axial ring guide may be greater than the axial shortening of thecable bundle generated in the actual section. Thus, in this embodiment,the bundling devices may be also secured on the cables at irregulardistances.

Since the radial support is connected to two bundling devices which arearranged to be rotatable relative to each other according to thelongitudinal axis of the cable bundle the radial support may be bentduring a twisting of the cable bundle. In order to prevent this, the twobundling devices may be additionally connected by a stiffener except theconnecting radial support. Through this stiffener the two bundlingdevices, which are connected with the radial support, are non-rotatablyconnected to each other which prevents a twisting of the cable bundle inthis area and a bending of the radial support.

Further details of the invention will become apparent from thedescription of the drawings.

In the drawings:

FIG. 1 shows a wind turbine,

FIG. 2 shows an upper part of the tower of the wind turbine,

FIG. 3 a shows a first embodiment of a bundling device,

FIG. 3 b shows a carrier of the bundling device,

FIG. 3 c shows a cross-section of the bundling device,

FIG. 4 shows a clamping clip of the bundling device,

FIG. 5 shows an insert of the clamping clip,

FIG. 6 a shows an axial plan view of a second embodiment of the bundlingdevice,

FIG. 6 b shows a radial plan view of a second embodiment of the bundlingdevice

FIG. 7 shows bundling device with loose guides

FIG. 8 a shows bundling device with radial supports,

FIG. 8 b shows ring guide for the radial guidance of the cable bundle,

FIG. 9 a shows a perspective view of the guiding device,

FIG. 9 b shows another perspective view of the guiding device,

FIG. 10 shows a perspective view of the bundling device,

FIG. 11 a shows a simplified side view of the guide device of FIG. 9,

FIG. 11 b shows a simplified plan view of the guiding device shown inFIG. 9,

FIG. 12 a shows a simplified side view of a further embodiment of aguiding device, and

FIG. 12 b shows simplified plan view of the guide device of FIG. 12 a.

FIG. 1 shows a wind turbine 1 with a tower 2, with a nacelle 8 which isrotatably mounted on the tower 2 about a tower axis 4 of the tower 2,and a rotor 9 which is connected to a generator located in the nacelle8. During the wind tracking—also known as “yawing”—the nacelle 8 isrotated about the tower axis 4 of the tower 2 in the horizontal plane inorder to perpendicularly rotate the rotor 9 in the wind and consequentlymaximize the energy output. Since the wind direction varies during theoperation of the wind turbine 1 or even rotates, it may be possible thatthe nacelle 8 is rotated around its own axis several times.

The statements used below about an axial direction 5, radial direction6, and circumferential direction 7 and the statements about the top andbottom apply to the longitudinal axis of the erected tower 2 of the windturbine 1.

FIG. 2 shows an upper part of the tower 2 of a wind turbine 1. In thetower 2 of the wind turbine 1, a plurality of current-conducting cables10, 11, 12, 13 are guided out of electrical components from the nacelle8 to the ground. This current-conducting cables 10, 11, 12, 13 are, forexample, cable 10 for electrically transmitting of three-phasealternating current (power cable 10), cable for ground conductor 11and/or signal and control cable 12. The current-conducting cables 10,11, 12, 13 are combined together to a cable bundle 14 in the upper partof the tower 2 through a plurality of bundling devices 17, 27. Thiscable bundle 14 is non-rotatably connected at the upper end 15 to thenacelle 8 which is rotatably mounted on the tower 2 and non-rotatablyconnected at the lower region 16 of the cable bundle 14 to the tower 2but hangs essentially freely in the tower 2. In order to support aradial movement of the cable bundle 14, the tower 2 also comprises aplurality of ring guides 19 which are fixedly connected to the tower 2and guided through the cable bundle 14.

FIGS. 3 a and 3 c show a bundling device 17 comprising a two-partcarrier 18 and a plurality of clamping clips 20. The annular carrier 18consists of two parts which are screwed together. The carrier 18 has inthe radial direction 6 a plurality of bores 21 which are used to fastenthe clamping clips 20. Furthermore, the carrier 18 also has bores 21 forsecuring, for example, radial supports 22. The individual parts of thecarrier 18 are also shown in FIG. 3 b. The clamping clips 20 are formedin a substantial V-shape and comprise two flanges with bores forattaching the clamping clips 20 to the carrier 18. The clamping clips 20are non-rotatably connected to the carrier 18 by means of screws 23 andform together with the carrier 18 a fastening device 24 for cables 10,11, 12. The fastening devices 24 are arranged so that they form anequilateral and polygonal structure. Through this structure the cables10, 11, 12 mounted in the fastening devices 24 have a distance D withrespect to each other at any time. By the V-shape of the clamping clip20 a receptacle 26 for cables 10, 11, 12 between the carrier 18 and theclamping clip is 20 is formed. Through the substantially triangularcross-section of the receptacle 26, particularly three-phase cables 10,12—each comprising three conductors 10 a, 10 b, 10 c, each of whichleads a phase—are held in an advantageous cloverleaf structure. Theclamping clip 20 and the cloverleaf structure of the cables 10, 12 arealso shown in FIG. 4. The fastening device 24 may also include an insert25. Through the insert 25, the size of the receptacle 26 of thefastening device 24 is reduced so that cables 12 with a smallercross-section can also be fastened. Such cables 12 may be three-phasecables of a rotor of a double-fed asynchronous generator. FIG. 5 showsthe insert 25 in a removed state.

FIGS. 6 a and 6 b show a further embodiment of the bundling device 27.FIG. 6 a shows the bundling device 27 based on an axial plan view andFIG. 6 b based on a radial plan view. In this embodiment, the fasteningdevices 29 are each rotatably fixed about an axis 30 which extends inthe radial direction 6 of the carrier 28. The fastening devices 29 formalone the receptacle 26 for the cables 10, 11, 12. Through the rotatablefixing, the fastening devices 29 can rotate with an oblique position ofthe cables 10, 11, 12 rotate so that the longitudinal axes of thereceptacle 26 of the fastening device 29 and cables 10, 11, 12 fastenedtherein also remain parallel even during an oblique position of thecables 10, 11, 12. Thereby, the loads acting on the cables 10, 11, 12and the fastening devices 29 are reduced.

The bundling device 17 shown in FIG. 7 includes a radially inner,circle-like cross-section 31. In accordance with a further embodiment,this cross-section 31 may be used to guide further cables 14, such asdata, control, or the signal cables. For this purpose, a further looseguide 33 is mounted on the carrier 18 of the bundling device 17, forexample in the form of a round steel bar bent into a helix which isfixed in radial bores 21 of the carrier 18. In FIG. 7, the cloverleafformation of the cables 10, 11, 12 which are fastened in the fasteningdevices 24 and the distance D of the cables 10, 11, 12 with respect toeach other can also be seen.

In FIG. 8 a, a cable bundle 14 with bundling devices 17 and radialsupport 22 is shown. In this embodiment, the radial supports 22 areformed as U-shaped rods which are respectively connected to two bundlingdevices 17 following one another in axial direction 5. The radialsupports 22 are arranged to be movable with the ring guide 19 shown inFIG. 8 b and connected to the tower 2. Through the radial support 22, itis prevented that the bundling devices 17 hook in a ring guide 19 duringan axial movement.

FIG. 9 a shows a perspective detail of the guiding device 34 and cableguide of the tower 2 of the wind turbine 1. FIG. 9 b also cites aperspective detail of the guiding device 34 and cable guide of the tower2. The tower wall 3 itself is not shown. Here the transition of thecable guiding from the cable bundle 14 into the cable guide 39 fixed tothe tower wall 3 is in the focus of consideration. The cable bundle 14and the lower region 16 of the cable bundle 14 are shown. The lowerregion of the cable bundle 14 merges into the cable loop 36 whichsubsequently merges into the cable guide 39 fixed with the tower. Withreference to the simplified FIGS. 11 a and 11 b, a side view and anaxial plan view of the guiding device 34, its function and arrangementis illustrated.

The cable bundle 14 leads downwards from the upper part of the tower 2,where the cable bundle 14 is fixedly connected to the rotatable nacelle8. The lower region 16 of the cable bundle 14 is arranged on the guidingdevice 34 by means of the bundling device 37 to be rotation-fixed in theaxial direction 5.

The guiding device 34 comprises a pivot arm 40 which is firstly arrangedon the tower 2 in a way of being rotatable about the horizontal pivotaxis 41. Moreover, the pivot arm 40 carries the bundling device 37 whichis attached via a support 42 on the pivot arm 40 i in a way of beingrotatable about the rotation axis 43. In this embodiment (FIG. 10), thebundling device 37 comprises a carrier 38, the support 42 connected tothe carrier and also on the carrier 38 arranged fastening devices 24 forfastening the cables 10, 11, 12 of the cable bundle 14. The fasteningdevices 24 are arranged in two axially offset rows on the carrier 38.

As already described, the cable bundle 14 is rotated corresponding tothe position of the nacelle 8 in the case of a rotation of the nacelle 8during the wind tracking. Here, the entire cable bundle 14 and thesystem of cable guiding are designed in such a manner that a maximumrotation of a twisting in a clockwise direction to a counterclockwisetwisting, or vice versa, of 2×900°, namely five revolutions is possible.With respect to the zero degree untwisted position, this means a maximumpossible twisting of the cable bundle 14 of 900 degrees in bothdirections. To be able to compensate for the axial shortening H of thecable bundle 14 associated with the twisting without negativelimitation, the guiding device 34, cable loop 36 and the cable support35 are arranged at the transition from the lower region 16 of the cablebundle 14 into the cable guide 39 fixed with the tower. The cablesupport 35 is connected to the tower wall 3.

If the cable bundle 14 is untwisted, the pivot arm 40 is located in asubstantially horizontal position, wherein the bundling device 37 issubstantially coaxially aligned with the tower axis 4. Now, if there isa wind tracking, then the nacelle 8 rotates and the cable bundle 14 istwisted. In this case, the cable bundle 14 is shortened in the axialdirection 5 and the lower region 16 of the cable bundle 14 is pulledupwards in the direction of the nacelle 8. This causes that the bundlingdevice 37 is moved with the pivot arm 40 upwardly, and the compensationof the shortening is carried out by the cable loop 36 which provides asupply cable reserve.

A further non-illustrated embodiment discloses that the pivot arm isslightly inclined downwards in an untwisted cable bundle. Thereby, thelower region of the cable bundle is disposed slightly radially offsetfrom the tower axis 4. This has the advantage that, with increasingrotation, the maximum deflection of the pivot arm is reduced in relationto the preceding embodiment.

The cables 10, 11, 12, 13 of the cable bundle 14 are connected to therespective cables 10, 11, 12, 13 of the cable loop 36. The cable loop 36is transferred via the cable support 35 into the cable guide 39 fixedwith the tower. Preferably, the cables 10, 11, 12, 13 of the cablebundle 14 or the cable 10, 11, 12, 13 of the cable loop 36 is configuredto be uninterrupted and integral with the respective cables 10, 11, 12,13 of the cable loop 36 or the cable guide 29 fixed with the tower. Ergopreferably, the cable 10, 11, 12, 13 are so constructed that theseuninterruptedly run from nacelle 8 down to the lower end of the tower 2.

The cable support 35 is designed in such a manner that the cables 10,11, 12, 13 of the cable loop 36 are disposed thereon such that betweenat least between the essential cables 10, 11, 12, such as power cables10, a minimum distance D is ensured. This configuration using thebundling device 14 on the guiding device 34 in conjunction with thecable loop 36 which is sorted on the cable support 35 and merges intothe tower-fixed cable guide 39, enables that the required distance D ofthe cables 10, 11, 12, (13) with respect to each other is alwaysobserved even in the cable loop 36 which is difficult to control.

FIG. 12 a and FIG. 12 b illustrate an alternative guiding device 44.Here, the means for supporting are formed as three rail assemblies 45,and each comprises a first rail element, e.g. a sliding carriage 46, anda second rail element which is formed for example as sliding rail 47which embraces the slide carriage 46 in the radial direction 6 and inthe circumferential direction 7. The sliding carriage 46 is mountedslidably in the axial direction 5 in the sliding rail 47 but fixed bythe sliding rail 47 in the circumferential and radial direction 6, 7.

The sliding carriage 46 is connected to the lower region 16 of the cablebundle 14 and in particular to the bundling device 37 which comprisesthe carrier 38 and fastening devices 24 arranged thereon. The slidingrail 47 is fixedly arranged in the tower 2. When the cable bundle 14 isshortened, the sliding carriage 46 slides upwards in the axial direction5 wherein the compensation of the displacement H is performed by thecable loop 36.

The combinations of features disclosed in the embodiments should not acton the invention in a limiting way, but the features of the differentembodiments can also be combined.

List of reference signs 1 wind turbine 2 tower 3 tower wall 4 tower axis5 axial direction 6 radial direction 7 circumferential direction 8nacelle 9 rotor 10 power cable 11 earthing conductor 12 cable 13 signaland control cable 14 cable bundle 15 end 16 lower region 17 bundlingdevice 18 carrier 19 ring guide 20 clamping clip 21 bore 22 support 23screws 24 fastening device 25 insert 26 receptacle 27 bundling device 28carrier 29 fastening device 30 axis 31 cross section 33 guide 34 guidingdevice 35 cable support 36 Cable loop 37 bundling device 38 carrier 39tower fixed cabling 40 pivot arm 41 pivot axis 42 support 43 rotationaxis 44 guiding device 45 rail arrangement 46 sliding carriage 47sliding rail D distance H displacement 1

1-8. (canceled)
 9. Tower for a wind turbine comprising, an upper end, onwhich a nacelle can be arranged to be rotatably supported, wherein atleast three cables are arranged along a axial direction in the tower andthus form a cable bundle, an upper end of the cable bundle non-rotatablyconnectable to the nacelle, and a lower region of the cable bundlenon-rotatably connected to the tower, wherein a guiding device for atleast partially fixing the lower region of the cable bundle on the toweris effectively arranged between the cable bundle and the tower, wherein:the guiding device has a pivot arm for supporting the lower region ofthe cable bundle in a radial direction and for supporting in acircumferential direction relative to the tower, the pivot arm isconnected rotatably about a pivot axis to the tower at its side facing atower wall, the pivot axis extends substantially horizontally andperpendicularly to the axial direction, and the guiding device isconfigured such that the lower region of the cable bundle is movablymounted in axial direction relative to the tower, but is substantiallyfixed in circumferential direction and radial direction relative to thetower.
 10. A tower according to claim 9, wherein a first end of cableloop is connected directly to the lower region of the cable bundle andthereby connected electrically therewith, and a second end of the cableloop is fixedly connected to the tower and electrically connected tofurther cables fixed with the tower.
 11. A tower according to claim 9,wherein the guiding device comprises a bundling device with fasteningdevices for receiving the cable wherein the bundling device is arrangedat the lower region of the cable bundle, and wherein the bundling deviceis configured in such a manner that in each state at least three cablesin the cable bundle have a minimum distance (D) with respect to eachother.
 12. A tower according to claim 10, wherein a cable support forarranging individual cables of the cable loop is provided to beconnected to the tower, wherein the cable support is configured in sucha manner and the cables can be arranged thereon in such a manner that ineach state at least three cables in the cable loop have a minimumdistance (D) with respect to each other.
 13. A tower according to claim11, wherein a number of fastening devices corresponds at least to thenumber of the cables.
 14. A tower according to claim 11, wherein thebundling device comprises a carrier, wherein the fastening devices arearranged on the carrier, and/or the carrier is formed at least partiallyby the fastening devices or the fastening devices are formed at leastpartially by the carrier.
 15. A tower according to claim 14, wherein thefastening devices are configured as clamping clips which are fastenedon, in particular screwed onto, the carrier, and each of which comprisesa receptacle for cables.
 16. A tower according to claim 9, wherein thebundling device is arranged at a side of the pivot arm facing the towerinterior in a way of being rotatable about a rotation axis, wherein therotational axis extends substantially horizontally and perpendicularlyto the axial direction.